The Perfect Mix of Old and New

The
centerpiece of the new “one-piece flow” process was a robotic
retrofit for grinding and polishing kitchen and bathroom fixtures
which combined interlinked high-volume production with
highly-flexible, order-controlled manufacturing. SHL implemented a
cost-effective, integrated solution using a mixture of existing,
overhauled, and new robotic arms.

The enterpiece of the new “one-piece flow” process was robotic retrofit for grinding and polishing kitchen and bathroom fixtures which combined interlinked high-volume production with highly-flexible, order-controlled manufacturing. SHL implemented a cost-effective, integrated solution using a mixture of existing, overhauled, and new robotic arms. Since
1984, KWC AG, part of the German Hansa-Group based in Stuttgart, has
been renowned for “Swiss Excellence” in the kitchen and bathroom
faucet sector. As the Swiss market leader, with approximately 380
employees, KWC manufactures its own products exclusively at its
Unterkulm, Switzerland, site and exports to 50 countries worldwide.
As with other industries, KWC’s business has experienced marked
changes over the ensuing years due to ever-increasing expectations of
design and functionality.

Furthermore,
the competitive pressures brought on by globalization require highly
productive and cost-efficient manufacturing systems. While this is
relatively easy to accomplish when using high automation levels in
settings involving volume-oriented production for larger batches, the
challenges are significantly greater with regard to order-based small
and midsized manufacturing. For KWC AG, all of the series production
systems for the company’s core competencies – casting, machining,
grinding, polishing, bright chromium plating, as well as component
assembly and final assembly – were in place from the beginning. The
introduction of a new line of kitchen and bathroom faucets was the
impetus for the search for a new, forward-looking manufacturing
philosophy. Roland Affolter, Production & Logistics Manager and
executive officer, explains:

We
were faced with a typical trade-off. While we had very powerful
production systems, we were often no longer able to use them
efficiently. We had been accustomed to stockpiling from series
production, but we found ourselves obligated to do order-based
manufacturing in order to make deliveries within a period of three
days. We needed different, highly flexible, and universally
applicable capacities. At the same time, we wanted to continue to
make our production processes leaner. In order to keep the costs of
our production system revision at reasonable levels, we decided to
gradually implement a comprehensive retrofit project. This also
allowed us to supply customers at full capacity during the renovation
phase.

The
"AIN" Project – Once Again, Courtesy of SHL

Today
we can say that Operation AIN (from the German “Alt in Neu"
for “old into new”) has been a success. Manufacturing and
intra-logistics expert Roland Affolter gives a large part of the
credit for this to long-term, proven partners such as SHL Automation
AG. SHL has been supplying and installing robotic grinding and
polishing systems at KWC for many years. This includes 13 complete
systems to date, two of which form part of the "AIN"
retrofit project. KWC’s specifications required SHL to reuse the
robotic grinding part from a grinding and polishing system designed
for a specific product and merge it with a new robotic polishing unit
and a new workpiece pallet conveyor system to form a flexible and
universally capable grinding and polishing cell.

The
new cell consists of a robotic grinding unit, a manual workstation
for any required rework, a robotic polishing unit, various control
panels, and of course the workpiece pallet conveyor system. While the
robotic grinding unit from the high-volume line was used, the robotic
polishing unit had to be built from scratch to allow it to be
integrated into the manufacturing and material flow process of the
stand-alone grinding and polishing cell. SHL supplied and installed a
new robotic polishing system, essentially comprised of a Kuka KR30/2
industrial robot with a KR C1 controller and basic clamping device,
four P1000 ROB polishing machines, and a pallet conveyor system.

A
Solution without Complications

The
scope of the project also included overhauling the existing robotic
grinding systems before finally reinstalling the complete set of
machinery as an integrated cell. The work was performed in stages,
first on Line 1A, and then on Line 1B.

The
project went smoothly without causing any bottlenecks in capacity or
delivery. This was because most of KWC’s production lines exist in
duplicate (for redundancy, availability, capacity and supply
security), and because the technicians and engineers from SHL had
tested their components and performed prep work in advance.

The
Quality Team Ensures “Zero Defect” Hand-off

Compared
to the former high-volume manufacturing processes in interlinked
lines, today’s workflow is as follows. For each robotic grinding
and polishing cell, a qualified skilled worker is responsible for
rework and inspection, as well as for loading workpiece pallets with
blanks, and for unloading the finished parts into their transport
containers. The worker places the fixtures (10-15, depending on model
and type) onto the workpiece pallet in the correct position. The
conveyor system moves the pallet toward the robotic grinding unit.
There, the pallet is completely emptied of workpieces, which the
robot machines and puts back on the pallet. Then, the conveyor system
transports the pallet to a manual workstation where an operator
inspects the workpieces and reworks them, if necessary.

A
Process that Is Both Highly Productive and Flexible at the Same Time

From
there, the pallet moves to the robotic polishing unit, where the
workpieces are again automatically processed. Then, the pallets
arrive at their final destination where a worker performs another
visual inspection on the finished parts, and puts the “OK” ones
into containers for the electroplating process. Thus operators
perform both monitoring and reworking functions, i.e., they are
responsible for their own process and quality control. Through the
process, the operators are supported by a programmer and tool setter,
who each support several lines or cells.

While
a little unusual, this manufacturing strategy is very pragmatic in
its design, and works very well with the parallel implementation of
the Kanban system with its related philosophy of worker supervision
and responsibility. Roland Affolter summarizes this as follows:

Integrating
robotics and grinding and polishing specialists in a kind of
manufacturing cell seemed to us the logical solution if we wanted to
achieve a manufacturing process for quality faucets that is both
highly productive and highly flexible. One-piece flow and
order-driven manufacturing in small series allows us to deliver any
requested product within three days. This worked so well, even during
our renovation and new installation phase, that we were always able
to deliver on time, despite this Herculean task. And last but not
least, our partnership with SHL saved the day again, particularly
because SHL technicians and engineers came through for us with a very
efficient integrated solution that made use of a mix of existing and
overhauled technologies, including new robotics.

...SHL
technicians and engineers came through for us again with a very
efficient integrated solution that made use of a mix of existing and
overhauled technologies which included new robotics...